This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
The subject matter disclosed herein relates to gas processing, and, more particularly, to systems and methods for using a process fluid to lubricate bearings of rotating equipment during gas processing.
Natural gas is a naturally occurring hydrocarbon gas mixture that may be combusted to provide energy or used as a chemical feedstock in the manufacture of plastics and other organic chemicals. Virgin natural gas (e.g., untreated natural gas), as it emerges from natural geologic reservoirs, contains varying amounts of sour gases, particularly carbon dioxide and hydrogen sulfide, also referred to as acid gases. Carbon dioxide reduces the calorific value of the natural gas, and hydrogen sulfide may transform into sulfur dioxide, sulfur trioxide, and/or sulfuric acid. One method for removing these sour gas components from virgin natural gas is to combine it with water and amine in a high pressure environment (e.g., in a contactor). This process allows the separation of the high quality natural gas from the sour gases.
Large amounts of energy may be expended in pressurizing the amine solutions used in the natural gas separation process, which may be lost (e.g., not recovered) when the sour gases are stripped from the amine solutions. A turbocharger, which includes a turbine section and a pump section, may be used to recover at least a portion of the energy from the amine solution exiting the contactor. Turbochargers generally rotate at high speeds, and as such, bearings of the turbocharger are lubricated to reduce wear of the turbocharger and to cool the turbocharger. For example, the turbocharger may be fitted with external oil lubricated bearings or process fluid lubricated bearings. However, oil lubricated bearings may increase the cost and complexity of the process as compared to process fluid lubricated bearings and may require dynamic shaft seals for proper implementation.